Method and device for preventing water burst of underground water of coal mine in front of dam

The invention discloses a method and device for preventing water burst of underground water of a coal mine in front of a dam. The method for preventing water burst of underground water of the coal mine in front of the dam comprises the steps that the building position of a dam body is preset, and a first filling area and a second filling area are sequentially arranged on the side, facing a mining stopping line, of the building position in the direction close to the mining stopping line; the second filling area is filled with first gangue with the lumpiness larger than a preset value; the first filling area is filled with second gangue with the lumpiness smaller than a preset value, and the edge of the building position is filled with the second gangue located at the bottom of the first filling area; and the dam body is built at the building position, and when the dam body is in contact with the top, the position between the second filling area and the dam body is filled with clay. The device for preventing wa